The off-ramp overpass that fell onto the southbound lanes of I-75 Monday night did not cause a lot of damage to the highway.
That doesn't surprise Andrew Hermann, past president of the American Society of Civil Engineers, who has been following the story. But he says the fact that the span did fall was surprising.
“Generally, they have demolition plans where they try to take into account all the possibilities as they’re taking down a bridge, to do it safely," Hermann said. "So it was very surprising to hear that it collapsed."
“Normally, the contractor will generate and submit a program, basically a scheme, step-by-step, as to how he’s going to take it down because public safety is very important, also the safety of the workers,” Hermann said.
Hermann has been a bridge engineer with Hardesty and Hanover consultants in New York for 41 years.
“They try to account for - as you take weight off one area, how does it affect other areas?," said Hermann. "So, it’s generally a procedure that’s laid out and done by experienced contractors who’ve done it before… It’s generally a very safe process.”
Workers with Kokosing were demolishing the overpass Monday night when it came down in an uncontrolled fall, killing 35-year-old Brandon Carl who was operating a backhoe on top of the road.
At the time, Cincinnati Police Chief Jeffery Blackwell said “hundreds of tons” of concrete and steel fell onto the four lanes of I-75. At a press conference on Tuesday, city officials expected the southbound interstate lanes would be closed for 24 to 48 hours for the investigation, clean up and repairs.
But when the debris was removed, the damage was limited to a 2-foot by 2-foot hole which does not come as a surprise to Hermann.
“When I read that, I kind of supposed to myself that it came down and that was the first area that the superstructure hit," Hermann said. "And that absorbed… a lot of the load."
He speculates “that one area took a concentrated hit and sort of tempered a lot of the collapse.”
The hole was patched and the road re-opened by 10 p.m. Tuesday.
Hermann said he would not anticipate deeper, unseen damage to the interstate pavement either.